DE102021212411A1 - Adjustable aperture for an optical beam path - Google Patents

Abstract

The invention relates to an adjustable diaphragm (8) for an optical beam path, having a plurality of diaphragm elements (1), each of which can be moved in a diaphragm plane (5) extending laterally to a passage axis (7), and sections of an edge of the diaphragm elements (1) depending on their respective current setting position, in each case delimit in sections an opening (9) around the passage axis (7). In addition, there are drives (11) for setting a respective setting position of the screen elements (1). According to the invention, the adjustable screen (8) is characterized in that each screen element (1) is designed as a cam disk or sector of a cam disk, which is rotated by an im The axis of rotation (2) directed essentially parallel to the passage axis (7) can be rotated; each screen element (1) has a number of differently shaped edge segments (4), so that a current setting position of the relevant screen element (1) is selected and approached for the purpose of setting a selected size and/or shape of the opening, so that a desired edge segment (4 ) a portion of the boundary of the opening (9) is formed; and a radial distance (3) of the edge segments (4) of a screen element (1) to the respective axis of rotation (2) increases at least over an angular range of the screen element (1).The invention also relates to an optical arrangement (15) and an operating method.

Description

The invention relates to an adjustable diaphragm according to the preamble of the main claim and an optical arrangement with an adjustable diaphragm and a method for operating such a diaphragm.

Apertures are often used in optical beam paths, both in illumination beam paths and in detection beam paths of optical devices, the opening width of which and possibly the shape of the (aperture) opening can be adjusted and adapted to different applications.

In particular when carrying out microscopy methods in which a sample to be observed is damaged by excessively intense illumination radiation (phototoxicity) and/or disadvantageous imaging effects are caused, an adaptation of the current illumination radiation is of great importance. In this case, the illumination beam path can be trimmed by means of an adjustable diaphragm.

Such screens fulfill different tasks. On the one hand, the proportion of the illumination radiation that reaches the sample is determined by the size of an aperture of the aperture (aperture). In addition, the illumination radiation can be adjusted in such a way that illumination radiation only strikes a currently observed region of the sample. Furthermore, by means of the shape of the opening, both the shape of an illuminated area of the sample can be influenced and the illuminated area can also be adapted to a shape of a detector present in the detection beam path for detecting detection radiation. For example, conventional camera chips primarily have rectangular dimensions. The use of rectangular diaphragms is therefore particularly useful in a luminous field diaphragm level (intermediate image).

Adjustable apertures also offer the possibility of influencing a resulting position of an illuminated area of the sample through a current positioning of the opening. On the other hand, due to mechanical play of the components involved, for example, an unwanted offset of the opening relative to the optical axis, for example of the illumination beam path, can occur.

A number of adjustable diaphragms are known from the prior art. Thus, DD 57 720 discloses an adjustable rectangular aperture with two pairs of aperture slides offset by 90° to one another. Lamellae are also often used, which are arranged symmetrically around an optical axis and which are simultaneously moved into or out of the beam path as required (see, for example, DT 25 57 885 A1 ; DE 80 16 658 U1 and DE 2053 089 A .

A disadvantage of the solutions according to the prior art is that the opening of the adjustable diaphragm can only be centered with respect to the optical axis with an additional adjustment device. In addition, the size and position of the opening can only be freely selected within narrow limits. This applies in particular when at least two screen elements are mechanically positively coupled to one another. In addition, greater positioning inaccuracies can occur due to the play in the coupling points (e.g. due to backlash).

The invention is based on the object of proposing an adjustable diaphragm which, in particular compared to the prior art, permits expanded adjustment possibilities for the size and/or the shape of a diaphragm opening. In addition, the centering of the diaphragm opening or the maintenance of a centering that has taken place should be simplified. In addition, a method for operating an adjustable aperture is to be proposed.

The task is solved with an adjustable diaphragm for an optical, in particular light-optical, beam path. The adjustable screen comprises a plurality of screen elements, each of which can be moved in a screen plane which extends laterally, essentially orthogonally, to a passage axis. The passage axis usually coincides with an optical axis of the beam path. Sections of the panel elements, in particular a segment of an edge (outer contour and/or inner contour; see below) of the relevant panel element, delimit in sections an opening (panel opening) around the passage axis depending on their respective current setting position. In addition, there are drives for setting a respective setting position of the panel elements.

An adjustable screen according to the invention is characterized in that each screen element is designed as a cam disk or as a sector of a cam disk, which is rotatable about a respective axis of rotation directed essentially parallel to the passage axis. The cam disc has a number of differently shaped sections of its respective edge, so that for the purpose of setting a selected size, shape and/or position of the opening, a current setting position of the screen element in question is selected and approached, in which a selected edge segment covers a section of the boundary of the opening forms. A resulting size, shape and / or position of the opening is determined by the combination all panel elements in their respective current setting positions. The diaphragm elements are designed in such a way that a radial distance between the edge segments, in particular successive edge segments, of a diaphragm element and the axis of rotation increases at least over an angular range of the cam disk.

The angular range is at least 90°, advantageously at least 180° or at least 270°. Each screen element can therefore be designed as a closed cam disk or in the form of a segment or sector, in which case the angular range of the increasing radial distance between the edge segments can be smaller than the entire extent of the screen element.

In one possible embodiment of the invention, the increase in the radial distance between the edge segments over the angular range can take place continuously. In this case, an edge segment is understood to mean a section of the panel element which essentially has a uniform radius of curvature. This changes slightly over the extent of the edge segment, for example by no more than 5% of the mean radial distance of the relevant edge segment. The beginning and end of an edge segment of this embodiment are therefore not fixed from the outset, but are each determined by its current participation in the delimitation of the opening.

In further possible embodiments of the adjustable screen according to the invention, the edge segments are each designed as rectilinear sections (line sections). In this case, either all line sections can be arranged in a sequential arrangement or at least two adjacent line sections can be formed with increasing radial distances from the axis of rotation and form steps with respect to one another. The line segments may be tangent to the curve radius or at an angle other than 90°, giving the edge of the screen member a sawtooth appearance (collectively referred to as a stepped or gradual gradient). The radial distance of a line section running at an angle not equal to 90° from the axis of rotation is determined, for example, in the middle of the relevant line section.

It is possible for a screen element to have both at least one segment with a continuous course and at least one segment with a stepped or sawtooth-like course.

In order to allow individual control of all screen elements and thus allow the greatest possible range of variation in the adjustable sizes and/or shapes of the opening, in further embodiments of the invention each screen element can be rotated independently of the other screen elements about the axis of rotation, which is essentially parallel to the passage axis. The rotation can advantageously be controlled by a motor or manually.

Stepper motors with limit switches (e.g. Hall sensors, fork couplers, reflex couplers), DC motors with encoders/rotary sensors and upstream gears can be used as motor drives, for example.

However, in a further embodiment of the invention it is possible for at least two of the screen elements to be coupled to one another, so that their rotations and adjustment positions are determined by the respectively selected coupling ratios. In such an embodiment, the number of setting options for the opening is limited compared to a separate drive for each diaphragm element.

A mechanical coupling or a control-related coupling is advantageous, for example, when at least one of the edge segments of at least one screen element protrudes beyond the center of the opening and intersects the passage axis. With such an embodiment, the opening of the adjustable aperture can be completely closed. A coupling of the screen elements arranged in a common screen plane can advantageously take place in such a way that an unwanted collision of the screen elements is prevented. For example, a control-technical coupling can prevent the screen elements from being able to assume positions at which contact or even collisions occur. A mechanical coupling to avoid collisions can be realized, for example, by projections, stops or the like, which avoid undesirable combinations of adjustment positions.

In addition to the controlled setting of the size and/or shape of the opening, the position of the opening can also be influenced by means of the adjustable screen according to the invention. The position of the opening is understood to mean in particular the lateral position of the center point, in particular the geometric center point of the opening, relative to the optical axis of a beam path directed through the opening.

One way of adjusting the position of the opening is to select adjustment positions for the individual screen elements. For example, the position can be shifted by a small distance when the two face each other Lying panel elements are set asymmetrically to each other. In this case, the opening is not delimited by those edge segments that correspond to one another, but by those with different radial distances.

A further possibility allows the position to be changed in a targeted manner over a greater distance. At least one of the screen elements can be displaced in its respective screen plane in a controlled manner in addition to the rotary movement. Such a shift can be effected by means of a further motorized drive or manually and allows, for example, an adjustment of the adjustable diaphragm. The displacement can take place along a guide. In further embodiments of the invention, a displacement can take place within the aperture plane, ie two-dimensionally. Additionally or alternatively, a displacement of the screen elements in the direction of the z-axis can also be possible.

The edge segments that act as a delimitation of the opening can be an outer contour of the respective screen element. In this way, at least two opposing screen elements can be arranged in a common screen plane without touching or overlapping.

In further embodiments of the adjustable screen according to the invention, the edge segments form at least sections of an inner contour of the screen element. The screen elements are designed, for example, as cam disks that have a recess, through the edge of which a region of the edge segment is formed. In this case, the outer contour of the screen element is not relevant for the delimitation of the opening. If the screen element is displaceable in the plane of the screen as described above, in further design options the displacement in the plane of the screen can be carried out so far that instead of the inner contour then alternatively an edge segment forming the outer contour in sections delimits the opening on one side. If there are several screen elements in a screen according to the invention, the inner contour of which serves to delimit the opening, these are to be arranged in different screen planes in order to avoid collisions.

For reasons of the course of the beam paths of individual rays, for example a bundle of rays of an illumination radiation, undesirable optical effects such as the stopping down of rays and diffraction effects can occur, which are essentially due to the design-related offset of the diaphragm elements along the optical axis.

In order to reduce such effects, in further embodiments of the invention the edge segments of the panel elements each have a bevel. The bevels of the diaphragm elements of a diaphragm plane end at the same position along the optical axis. The bevels are advantageously designed in such a way that they protrude into the beam path in the same position of a side face of the screen element that extends in the respective screen plane (see Fig 4 ). In this way, optical effects are reduced that can occur in the direction of the optical axis due to the material thickness (thickness) of the diaphragm element in question. As a result of the very small dimension of the chamfered diaphragm edge, it can be arranged very precisely in an intermediate image plane. If several screen elements are arranged in adjacent screen planes, the respective chamfers can be formed on those side surfaces of adjacent screen elements that lie directly next to one another.
The angles of the bevels are advantageously selected in such a way that reflected rays do not reach the camera or the detector or the eyepiece and thus generate disruptive scattered light.

If the dimensioning of the diaphragm elements and their arrangement in the z-direction are appropriately coordinated, any longitudinal color errors that may occur can also be reduced with the adjustable diaphragm according to the invention.

As already mentioned above in connection with an optional bevel, in an adjustable diaphragm according to the invention, diaphragm elements can be arranged in the direction of the optical axis in at least two diaphragm planes orthogonal to the optical axis. Advantageously, these can be moved into or out of the beam path in different directions.

For example, the diaphragm elements of the different diaphragm planes can bear against one another in the direction of the optical axis with their mutually facing side surfaces. The contact surfaces caused by the mutually touching areas of the side surfaces can advantageously be provided with a sliding coating (e.g. PTFE; polytetrafluoroethylene), which enables the side surfaces to slide against one another with low friction and which reduces static friction effects, which are disadvantageous, for example Beginning of a sliding movement can occur.

In other versions, a distance (air gap) can be maintained between the screen elements of different screen planes. With increasing distance, however, it becomes more difficult to get as much of the optical effect as possible to position the diaphragm elements involved in the adjustable diaphragm or the corresponding edge segments in a common plane or within a small distance in the direction of the passage axis. The common plane is in particular an intermediate image plane.

The adjustable diaphragm according to the invention can be present and used in an optical arrangement, for example in an illumination beam path. An illumination beam path can be used to shape and guide radiation and for this purpose includes, for example, optical elements for imaging the radiation in an intermediate image plane. Furthermore, there is an adjustable diaphragm according to the invention, which is arranged in particular in an intermediate image plane. In addition, there is at least one optical element (lens) for imaging the image of the adjustable aperture in a sample space. The image of the adjustable diaphragm can be projected onto or into an object to be illuminated and/or imaged, for example a biological sample or a material sample. If, in addition, there are motor drives for the controlled movement of the screen elements, there is a control unit which is designed and configured to generate setting commands for the individual drives. An illumination beam path as described above can be present in a microscope.

In further embodiments, the optical arrangement can be a detection beam path, along which a detected detection radiation is directed onto a detector. A detector can be, for example, a camera or a camera chip (eg CCD chip, CMOS chip or arrays of photomultipliers or photo avalanche diodes such as PMT arrays; SPAD arrays).

It is possible for an adjustable diaphragm according to the invention to be arranged in an illumination beam path and/or in a detection beam path, in particular of a microscope.

The control unit can be, for example, a computer or an FPGA (field programmable grid array).

In further embodiments of an optical arrangement, the adjustable diaphragm according to the invention can be arranged outside of an intermediate image plane, for example in a section of collimated radiation of the beam path.

The adjustable aperture according to the invention allows a variety of shapes and/or sizes of the opening to be set. At least some of the possible shapes may not be ideal for light-optical beam shaping. For example, it is possible that at certain adjustment positions of the screen elements present, openings are created which have a cushion shape and/or long, tapering corner areas. In a beam path, in particular in an illumination beam path, there can therefore be at least one optical means such as an AOTF (acousto optic tunable filter), through the effect of which errors and deviations in the beam of rays are corrected or can be corrected (correction unit), which as a result of such Forms of opening occur. Thus, distortions caused by the structure of the beam path can be used and/or corresponding distortions can be brought about in order to reduce errors caused by the adjustable diaphragm. For example, a pincushion distortion of the adjustable diaphragm can be at least reduced by a corresponding barrel distortion in the course of the beam path.

The adjustable diaphragm according to the invention according to one of the possible embodiments described can be operated by detecting the current setting position of each diaphragm element. In addition, an actual configuration of the diaphragm element as a cam is stored so that it can be called up repeatedly. In this way, it is known which edge segment or which edge segments are currently facing the passage axis, which usually coincides with the optical axis. In addition, a desired shape and size and/or position to be set of the opening, which is delimited in sections around the passage axis by the screen elements, is determined. A determination is therefore made as to the opening to be set, and this selection is compared with a currently available setting of the adjustable diaphragm.

The determination of the shape, size and/or position of the opening can take place iteratively in that, starting from a current setting situation, the screen elements are adjusted and at the same time the effect of the opening created in this way is recorded and evaluated. For example, the signals of a detector can be evaluated in each case and related to the current setting positions of the screen elements and the resulting opening. For such a procedure (feedback control), a sample with known properties, for example a reference sample or a reference object, can be illuminated. It is also possible to calculate the respectively required adjustment positions of the screen elements and the control commands required for this, for example by means of a simulation. Further options are given with pre-created tables (LUT; look-up table).

The complex interaction of the individual screen elements, in particular if they can be rotated independently of one another and, if appropriate, also be laterally displaceable, can advantageously be evaluated using a computer.

If the current actual setting positions of the diaphragm elements are known and the desired size, shape and/or position of the opening is determined, the diaphragm elements are moved accordingly into the required desired setting positions. If this is not done manually, corresponding control commands are generated, the execution of which brings the screen elements into the desired setting positions that have been determined.

If only the shape and/or size of the opening is adjusted, a virtual center point of the opening remains stationary in each current adjustment position and is pierced by the passage axis. The opening thus remains centered relative to the passage axis. In addition or as an alternative, it is possible to control the screen elements in such a way that, in addition to the shape and/or size of the opening, its lateral position is also changed. The virtual center of the opening is shifted laterally to the passage axis.

• 1 eine schematische Darstellung eines ersten Ausführungsbeispiels eines erfindungsgemäßen Blendenelements mit einem kontinuierlich zunehmenden radialen Abstand;
• 2 eine schematische Darstellung eines zweiten Ausführungsbeispiels eines erfindungsgemäßen Blendenelements mit einem stufenweise zunehmenden radialen Abstand;
• 3 eine schematische Darstellung eines dritten Ausführungsbeispiels eines erfindungsgemäßen Blendenelements mit einem stufenweise zunehmenden radialen Abstand und Randsegmenten mit je einer Fas 4 eine vergrößerte Darstellung eines Ausschnitts eines ersten Ausführungsbeispiels einer erfindungsgemäßen verstellbaren Blende mit gefasten Randsegmenten zweier nebeneinander angeordneter Blendenelemente;
• 5 eine schematische Darstellung eines zweiten Ausführungsbeispiels einer erfindungsgemäßen verstellbaren Blende mit Blendenelementen mit einem kontinuierlich zunehmenden radialen Abstand in einer ersten Betriebsstellung;
• 6 eine schematische Darstellung des Ausführungsbeispiels einer erfindungsgemäßen verstellbaren Blende mit Blendenelementen mit einem kontinuierlich zunehmenden radialen Abstand in einer zweiten Betriebsstellung;
• 7 eine schematische Darstellung des Ausführungsbeispiels einer erfindungsgemäßen verstellbaren Blende mit Blendenelementen mit einem kontinuierlich zunehmenden radialen Abstand in einer dritten Betriebsstellung;
• 8 eine schematische vergrößerte Detaildarstellung des Ausführungsbeispiels einer erfindungsgemäßen verstellbaren Blende mit Blendenelementen mit einem kontinuierlich zunehmenden radialen Abstand in der dritten Betriebsstellung;
• 9 eine schematische Detaildarstellung eines dritten Ausführungsbeispiels einer erfindungsgemäßen verstellbaren Blende mit Blendenelementen mit einem stufenweise zunehmenden radialen Abstand in einer Ansicht schräg von hinten;
• 10 eine schematische Darstellung des dritten Ausführungsbeispiels einer erfindungsgemäßen verstellbaren Blende mit Blendenelementen mit einem stufenweise zunehmenden radialen Abstand in einer ersten Betriebsstellung;
• 11 eine schematische Darstellung des dritten Ausführungsbeispiels einer erfindungsgemäßen verstellbaren Blende mit Blendenelementen mit einem stufenweise zunehmenden radialen Abstand in einer zweiten Betriebsstellung;
• 12 eine schematische Darstellung des dritten Ausführungsbeispiels einer erfindungsgemäßen verstellbaren Blende mit Blendenelementen mit einem stufenweise zunehmenden radialen Abstand in einer dritten Betriebsstellung;
• 13 eine schematische Darstellung eines vierten Ausführungsbeispiels einer erfindungsgemäßen verstellbaren Blende mit Blendenelementen mit einem kontinuierlich zunehmenden radialen Abstand und mit lateral verstellbaren Blendenelementen;
• 14 eine schematische Darstellung eines fünften Ausführungsbeispiels einer erfindungsgemäßen verstellbaren Blende mit Blendenelementen mit einem stufenweise zunehmenden radialen Abstand und mit verstellbaren Blendenelementen in vier Blendenebenen;
• 15 eine schematische Darstellung eines sechsten Ausführungsbeispiels einer erfindungsgemäßen verstellbaren Blende mit Blendenelementen mit einem stufenweise zunehmenden radialen Abstand, wobei die Blendenelemente durch Sektoren einer Kurvenscheibe gebildet sind;
• 16 eine schematische Darstellung eines vierten Ausführungsbeispiels eines erfindungsgemäßen Blendenelements mit einem stufenweise zunehmenden radialen Abstand, wobei die Randsegmente eine Innenkontur bilden;
• 17 eine schematische Darstellung eines siebten Ausführungsbeispiels einer erfindungsgemäßen verstellbaren Blende, wobei die Randsegmente der Blendenelements einen stufenweise zunehmenden radialen Abstand aufweisen und eine Innenkontur bilden;
• 18 eine schematische Darstellung eines achten Ausführungsbeispiels einer erfindungsgemäßen verstellbaren Blende mit zwei Blendenelementen, die jeweils mindestens eine spiralförmige Ausnehmung aufweisen;
• 19 eine schematische Darstellung eines ersten Ausführungsbeispiels einer erfindungsgemäßen optischen Anordnung mit einer verstellbaren Blende im Beleuchtungsstrahlengang; und
• 20 eine schematische Darstellung eines zweiten Ausführungsbeispiels einer erfindungsgemäßen optischen Anordnung mit einer verstellbaren Blende im Detektionsstrahlengang.

The invention is explained in more detail below using exemplary embodiments and illustrations. Show it:

• 1 a schematic representation of a first embodiment of a screen element according to the invention with a continuously increasing radial distance;
• 2 a schematic representation of a second embodiment of a screen element according to the invention with a stepwise increasing radial distance;
• 3 a schematic representation of a third embodiment of a screen element according to the invention with a stepwise increasing radial distance and edge segments, each with a Fas 4 an enlarged view of a section of a first embodiment of an adjustable panel according to the invention with chamfered edge segments of two panel elements arranged next to one another;
• 5 a schematic representation of a second embodiment of an adjustable diaphragm according to the invention with diaphragm elements with a continuously increasing radial distance in a first operating position;
• 6 a schematic representation of the embodiment of an adjustable diaphragm according to the invention with diaphragm elements with a continuously increasing radial distance in a second operating position;
• 7 a schematic representation of the embodiment of an adjustable diaphragm according to the invention with diaphragm elements with a continuously increasing radial distance in a third operating position;
• 8th a schematic enlarged detail view of the embodiment of an adjustable diaphragm according to the invention with diaphragm elements with a continuously increasing radial distance in the third operating position;
• 9 a schematic detailed representation of a third embodiment of an adjustable diaphragm according to the invention with diaphragm elements with a gradually increasing radial distance in a view obliquely from behind;
• 10 a schematic representation of the third embodiment of an adjustable diaphragm according to the invention with diaphragm elements with a stepwise increasing radial distance in a first operating position;
• 11 a schematic representation of the third embodiment of an adjustable diaphragm according to the invention with diaphragm elements with a stepwise increasing radial distance in a second operating position;
• 12 a schematic representation of the third embodiment of an adjustable diaphragm according to the invention with diaphragm elements with a stepwise increasing radial distance in a third operating position;
• 13 a schematic representation of a fourth embodiment of an adjustable diaphragm according to the invention with diaphragm elements with a continuously increasing radial distance and with laterally adjustable diaphragm elements;
• 14 a schematic representation of a fifth embodiment of an adjustable diaphragm according to the invention with diaphragm elements with a stepwise increasing radial distance and with adjustable diaphragm elements in four diaphragm planes;
• 15 a schematic representation of a sixth embodiment of an adjustable diaphragm according to the invention with diaphragm elements with a stepwise increasing radial distance, wherein the Aperture elements are formed by sectors of a cam;
• 16 a schematic representation of a fourth embodiment of a screen element according to the invention with a stepwise increasing radial distance, the edge segments forming an inner contour;
• 17 a schematic representation of a seventh embodiment of an adjustable screen according to the invention, wherein the edge segments of the screen element have a stepwise increasing radial distance and form an inner contour;
• 18 a schematic representation of an eighth embodiment of an adjustable diaphragm according to the invention with two diaphragm elements, each having at least one spiral recess;
• 19 a schematic representation of a first embodiment of an optical arrangement according to the invention with an adjustable diaphragm in the illumination beam path; and
• 20 a schematic representation of a second embodiment of an optical arrangement according to the invention with an adjustable diaphragm in the detection beam path.

In the following exemplary embodiments, the same technical elements are denoted by the same reference symbols.

In a first exemplary embodiment of a screen element 1 according to the invention in the form of a cam disk, the radius between an axis of rotation 2 of the screen element 1 and its edge increases continuously ( 1 ). If sections of the peripheral edge are viewed as edge segments 4, their radial distance 3 from the axis of rotation 2 therefore increases over the entire circumference of the screen element 1 and after a revolution of 360° jumps back to the initial radial distance 3 (example with arrows in full line or shown with a solid broken line). An outer contour 13 of the screen element 1 is defined by the edge segments 4 . The panel element 1 essentially extends in a plane that is spanned here by the x and y axes of a Cartesian coordinate system. The axis of rotation 2 is directed out of the plane of the drawing along the z-axis. Such an embodiment allows a determination of the respective limit of a diaphragm opening 9 (see below 4 until 16 ) involved sections of the edge, i.e. the thus defined edge segments 4.

In a second exemplary embodiment of the screen element 1 according to the invention, its edge is formed from individual edge segments 4 which are offset stepwise relative to one another ( 2 ). The edge segments 4 therefore have a stepwise increasing radial distance 3 from the axis of rotation 2 over the circumference of the screen element 1 . The edge segments 4 facing the aperture 9 in a respective set position of the aperture element 1 in question delimit the latter.

According to a third exemplary embodiment, the screen element 1 can have a number of edge segments 4 which are provided with a bevel 6 ( 3 ). Such an embodiment can be implemented both on screen elements 1 with a continuous edge and increasing radial distance 3, on screen elements 1 with a stepwise increasing radial distance 3 and on screen elements 1 with a sectionally continuously or stepwise increasing radial distance 3 of the edge segments 4.

The bevel 6 is used to reflect impinging rays of an illumination radiation or a detection radiation out of the beam path in order to avoid undesired scattered light on the edge segment 4 and on an adjustable aperture 8 (see 4 ) to counteract.

A possible arrangement of such screen elements 1 in an adjustable screen 8 according to the invention is shown in 4 shown schematically as a side section. In the exemplary embodiment, a first screen element 1.1 and a second screen element 1.2 are arranged in a first screen plane 5.1. In the current setting positions of the diaphragm elements 1.1 and 1.2, an edge segment 4 faces the passage axis 7, which coincides with the optical axis of the beam path, and delimits the diaphragm opening 9 in the first diaphragm plane 5.1. The chamfer 6 runs obliquely towards the passage axis 7 . In addition to the arrangement of the two screen elements 1.2 and 1.2, a third screen element 1.3 and a fourth screen element 1.4 are present (only a sector of the third screen element 1.3 is shown for drawing reasons). The effective current width of the diaphragm opening 9 is determined by the current adjustment positions of the diaphragm elements 1.1 to 1.4. The bevels 6 of the diaphragm elements 1.1 to 1.4 converge on a common virtual point of intersection within the diaphragm opening 9. This design together with a spatially close assembly of the aperture elements 1.1 and 1.2 of the first aperture level 5.1 and the aperture elements 1.3 and 1.4 of the second aperture level 5.2 causes an effective width of the aperture 9, which is particularly useful for use in an intermediate image with a shallow depth of field.

In other possible embodiments of an adjustable diaphragm 8 according to the invention, only three diaphragm elements 1.1 to 1.3 can be present, the axes of rotation 2 of which are, for example, parallel and offset by 120° to one another.

In the 5 a second exemplary embodiment of the adjustable diaphragm 8 according to the invention is shown in a view along the z-axis. The first two diaphragm elements 1.1 and 1.2 are arranged in the first diaphragm plane 5.1 facing the viewer, while in the second diaphragm plane 5.2 (for the representation of the two diaphragm planes see also 4 ) The third and fourth screen element 1.3 and 1.4 are located. The screen elements 1.1 to 1.4 shown are mounted on a carrier plate 10. FIG. All diaphragm elements 1.1 to 1.4 have a continuously increasing radial distance 3. In the illustrated first operating position of the adjustable screen 8 according to the invention, the opening 9 is delimited by edge segments 4 of the screen elements 1.1 to 1.4 and is determined in terms of its shape, size and position with respect to the passage axis 7. Since the edge segments 4 are rounded over their respective course, the opening 9 is slightly cushion-shaped. The imaging errors or distortions that may be caused by this can optionally be corrected by a correction unit 22 arranged in the course of the beam path (see, for example, 20 ) are compensated.

A second operating position of the adjustable aperture 8 is in 6 shown. The transition areas, at which the edge segments 4 with the smallest and the largest radial distance 3 are immediately adjacent, are delivered to the opening 9 and delimit it.

In a third operating position of the adjustable diaphragm 8 shown as an example, the adjustment positions of the diaphragm elements 1.1 to 1.4 are selected such that the transition areas are as close together as possible, resulting in the smallest possible opening 9 along the passage axis 7, as is shown in FIG 7 and 8th (enlarged detail view) is shown.

In a third exemplary embodiment of an adjustable diaphragm 8 according to the invention, diaphragm elements 1.1 to 1.4 are present, which have a radial distance 3 that increases in steps. In a rear view ( 9 ) a drive 11 is shown for each panel element 1.1 to 1.4, which are advantageously motorized and can be controlled by means of a control unit 12 via suitable data lines (only one shown as an example). Alternatively, manually operated drives 11 can be provided. In one embodiment, the screen elements 1.1 to 1.4, or others, are supported by the bearings of the respective drives 11. Alternatively, these can have a separate bearing. They are then connected to the drive 11 via a clutch or directly in a mechanical connection suitable for the transmission of actuating forces.

The adjustable aperture 8 according to the third embodiment is in 10 in a first, in 11 in a second and in 12 in a third operating position (similar to the 5 until 7 ) shown. As for example in 10 can be seen, the opening 9 does not cause, for example, pincushion distortions due to the partially straight edge segments 4 in many of the possible combinations of setting positions of the screen elements 1.1 to 1.4 (see, on the other hand, 5 and 6 ).

In all versions of the adjustable diaphragm 8 according to the invention, the diaphragm elements 1.1 and 1.2 or 1.3 and 1.4 of a respective diaphragm plane 5.1 or 5.2 are arranged relative to one another such that collisions within the respective diaphragm planes 5 are avoided. In the direction of the passage axis 7 (direction of the z-axis), this distance is advantageously set as small as possible in order to position the edge segments 4 at the opening 9 within the depth of field of the intermediate image ZB. In the case of an optionally possible initialization drive, an intelligent driving regime must be observed in order to avoid collisions.

This collision avoidance is particularly important in a fourth exemplary embodiment of the adjustable screen 8 according to the invention, in which the screen elements 1.1 to 1.4 can each be laterally adjusted individually or coordinated with one another. Such a lateral adjustment option is in 13 exemplified by arrows on the respective axes of rotation 2 . In addition to setting different sizes of the opening 9, such a lateral adjustment option can also be used to change the position of the opening 9, in particular with respect to the passage axis 7.

In a further possible embodiment of the invention, the screen elements 1 can be arranged in the respective screen planes 5 laterally displaced relative to one another. As a result, the resulting infeed directions of the edge segments 4 in a plan view of the screen 8 are not approximately 90° but can deviate from this by up to 45°, for example. By such an arrangement of the panel elements 1 relative to each other For example, the expression of a “cushion shape” of the opening 9 can be effected uniformly around the optical axis in order to reduce the adverse effect of such a shape of the opening 9. In an alternative embodiment, all or selected diaphragm elements 1 that are present can be rotated as a whole about the axis of rotation 7 in order to thereby achieve a shape of the opening 9 that causes few aberrations.

In further embodiments of the invention, the screen elements 1 can be adjusted laterally, ie in an x-y plane and/or in the direction of the z-axis (z-direction). In this way, the screen elements can be tilted, for example in order to convert a spiral course of the edge segments into a circular course.

The exemplary embodiments of an adjustable diaphragm 8 shown so far have diaphragm elements 1 in two diaphragm planes 5.1 and 5.2. In other versions, more screen elements 1 and additional screen planes 5 can be present, as is shown by way of example in 14 is shown. In addition to the diaphragm elements 1.1 to 1.4 in the two diaphragm planes 5.1 and 5.2, two further diaphragm elements 1.5 and 1.6 are arranged in a third diaphragm plane 5.3 and diaphragm elements 1.7 and 1.8 in a fourth diaphragm plane 5.4. In the illustrated embodiment, the respective radial distance 3 (see 1 until 3 ) gradually. In other possible embodiments, the radial distance 3 can increase continuously. The diaphragm elements 1.1 to 1.8 are advantageously mounted close to one another along the passage axis 7 in order, for example, to lie within the depth of field of an intermediate image.

It is also possible for diaphragm elements 1 with a stepwise increase and diaphragm elements 1 with a continuous increase in the radial distance 3 to be combined in an adjustable diaphragm 8 according to the invention of every possible embodiment. For example, one embodiment each can be arranged in the different diaphragm levels 5 . Furthermore, in all of the exemplary embodiments, screen elements 1 can be present on which sectors with both a stepwise increase and a continuous increase in the radial distance 3 are present. All these options can also be combined with each other.

The aperture elements 1, for example 1.1 to 1.4 ( 15 ) can be formed in a further embodiment of the invention as sectors of a cam. Although the number of possible configurations of the opening 9 is reduced in this way, the installation space required for the adjustable diaphragm 8 can advantageously be reduced. In the exemplary embodiment shown, the diaphragm elements 1.1 to 1.4 are each formed as a quarter of a cam disk and have a continuous increase in the radial distance 3.

In all the embodiments of the invention described so far, the outer contour 13 of the respective panel element 1 is designed and provided to limit the opening 9 . In further possible embodiments of the panel elements 1 according to the invention, an inner contour 14 can be formed by the edge segments 4 (only a few are designated as examples), which is used to limit the opening 9 (see, for example, 17 ) is provided. In the 16 Such a screen element 1 is shown with a stepwise increasing radial distance 3 of the edge segments 4 from the axis of rotation 2 . The panel element 13 naturally also has an outer contour 13 .

Aperture elements 1 with inner contours 14 can be used in an adjustable aperture 8 according to the invention 17 be used. In four aperture levels 5.1 and 5.4 (compare also 14 ) the panel elements 1.1 to 1.4 are arranged in such a way that their edge segments 4 delimit the opening 9 depending on the individual setting position and accordingly determine a shape, size and/or position of the opening 9. The individual screen elements 1.1 to 1.4 can be rotated by means of individual drives 11, which act on the respective outer contour 13, for example by means of a toothed or friction wheel.

In further variants of the adjustable screen 8, the screen elements 1.1 to 1.4 can be adjusted laterally to such an extent that the outer contour 13 of at least one screen element 1.1 to 1.4 serves as a delimitation of the opening 9 instead of its inner contour 14 (not shown).

Another possible embodiment of an adjustable diaphragm 8 according to the invention has, for example, two diaphragm elements 1.1 and 1.2 ( 18 ). The first screen element 1.1 is located in the first screen plane 5.1 while the second screen element 1.2 is arranged in the second screen plane 5.2. The diaphragm elements 1.1 and 1.2 each have at least one recess 23. The recesses 23 are narrow in relation to the base area of the respective panel element 1.1, 1.2 and are designed, for example, as spirally arranged slots. The course of each of the recesses 23 shows a changing radial distance 3 (shown only once) from the axis of rotation 2. In addition, the clear width of each recess 23 can vary over the course. There are webs 24 available through which an inner part of the screen element 1.1, 1.2 with an outer part of the panel element 1.1, 1.2 is mechanically connected.

In other possible embodiments of the invention, at least two recesses 23 can be formed in a screen element 1.1 and/or 1.2. The aperture elements 1.1, 1.2 must then be approached in a controlled manner so that the recesses 23 do not overlap in an undesired manner.

The diaphragm 8 according to the invention in one of its versions can be part of an optical arrangement 15 with an adjustable diaphragm 8 ( 19 ). Thus, the optical arrangement 15 can be an illumination beam path 16 along which radiation from a light source 17 is guided. The radiation coming divergently from the light source 17 is collimated by means of optical elements 18, in particular by means of optical lenses, and directed into a further optical element 18 by an optionally present color splitter 19. Due to its effect, the radiation is directed into an intermediate image plane ZB, in which the adjustable diaphragm 8 is arranged. Depending on the current setting of the diaphragm elements 1 of the adjustable diaphragm 8, the radiation in the intermediate image plane ZB is shaded. The radiation shielded in this way is guided to an objective 20 by means of further optical elements 18 and directed by its action, for example, into a sample space or onto a sample located there (neither of which are shown).

The drives 11 of the panel elements 1 and the light source 17 can be set or regulated by means of the control unit 12 .

The adjustable diaphragm 8 according to the invention can also be arranged in a beam path 16, designed as a detection beam path, of an optical arrangement 15, for example a microscope 15 ( 20 ). In this case, the illumination of a sample (not shown) as to 19 described, whereby in the intermediate image plane ZB of the illumination beam path there does not have to be a diaphragm, but - as for example in 18 indicated - may be present.

The detection radiation collected by the lens 20 is reflected into the detection beam path by the action of the color splitter 9 (broken solid line) and directed by an optical element 18 into an intermediate image plane ZB in which the adjustable diaphragm 8 is arranged. According to the current setting positions of the diaphragm elements 1, peripheral rays of the detection radiation are blocked, as is shown schematically. The remaining beams pass through the opening 9 of the adjustable diaphragm 8 to a correction unit 22 optionally present in the beam path, by means of which imaging errors, such as distortions, can be reduced. The corrected detection radiation is imaged on a detector 21 and recorded.

The drives 11, the light source 17, the detector 21 and/or the correction unit 22 are connected to the control unit 12 and can be controlled by it. The control unit 12 can also be configured in such a way that it evaluates the captured image data of the detector 21 . One goal of the evaluation can be to determine data on the optical effect of the current settings of light source 17, adjustable aperture 8 and/or correction unit 22 and, if necessary, to generate control commands based on this data, the execution of which changes the optical effects in the desired way or to a changed imaging situation (e.g. a different sample and/or a different imaging method) can be reacted to.

Reference List

1

aperture element

1.1

first aperture element

1.2

second aperture element

1.3

third aperture element

1.4

fourth aperture element

2

axis of rotation

3

radial distance

4

marginal segment

5

aperture level

5.1

first aperture level

5.2

second aperture level

6

chamfer

7

Through axis, optical axis (beam path)

8th

adjustable aperture

9

aperture, aperture

10

backing plate

11

drive (for an aperture element)

12

control unit

13

outer contour

14

inner contour

15

optical arrangement, microscope

16

Beam path (illuminating beam path, detection beam path)

17

light source

18

optical elements, optical lenses

19

color divider

20

lens

21

detector

22

correction unit

Eg

intermediate image

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• WO 2557885 A1 [0006]
• DE 8016658 U1 [0006]
• DE 2053089 A [0006]

Claims (15)

Adjustable diaphragm (8) for an optical beam path, comprising - a plurality of diaphragm elements (1), which are each movable in a diaphragm plane (5) extending laterally to a passage axis (7) and dependent sections of an edge of the diaphragm elements (1). their respective current setting position in each case partially delimit an opening (9) around the passage axis (7); - as well as drives (11) for setting a respective adjustment position of the screen elements (1), characterized in that - each screen element (1) is designed as a cam disk or sector of a cam disk, which is directed around a respective one that is essentially parallel to the passage axis (7). Axis of rotation (2) is rotatable; - Each screen element (1) has a number of differently shaped edge segments (4), so that for the purpose of setting a selected size and/or shape of the opening, a current setting position of the relevant screen element (1) is selected and approached, so that a desired edge segment ( 4) a portion of the perimeter of the opening (9) is formed; and - a radial distance (3) of the edge segments (4) of a screen element (1) to the respective axis of rotation (2) increases at least over an angular range of the screen element (1). Adjustable aperture (8) after claim 1 , characterized in that the angular range is at least 90°, advantageously at least 180°, at least 270°. Adjustable aperture (8) after claim 1 or 2 , characterized in that at least two of the panel elements (1) are coupled to one another, so that their rotations and adjustment positions are determined by the respectively selected coupling ratios. Adjustable aperture (8) after claim 1 or 2 , characterized in that each screen element (1) is rotatable independently of the other screen elements (1) about the axis of rotation (2) which is essentially parallel to the passage axis (7). Adjustable screen (8) according to one of the preceding claims, characterized in that the radial distance (3) increases continuously over the angular range. Adjustable screen (8) according to one of the preceding claims, characterized in that the edge segments (4) are each designed as line segments. Adjustable screen (8) according to one of the preceding claims, characterized in that at least one of the screen elements (1) can be displaced in the respective screen plane (5) in a controlled manner in addition to the rotary movement. Adjustable screen (8) according to one of the preceding claims, characterized in that the edge segments (4) form an outer contour (13) of the screen element (1). Adjustable screen (8) according to one of the preceding claims, characterized in that the edge segments (4) form an inner contour (14) of the screen element (1). Adjustable screen (8) according to one of the preceding claims, characterized in that the edge segments (4) of the screen elements (1) each have a bevel (6). Adjustable screen (8) according to one of the preceding claims, characterized in that screen elements (1) are arranged in the direction of the passage axis (7) in at least two screen planes (5, 5.1, 5.2). Adjustable aperture (8) after claim 11 , characterized in that the panel elements (1) of the adjacent panel planes (5) abut one another laterally and the contact surfaces that exist in this way are provided with a sliding coating. Optical arrangement (15) for shaping and guiding radiation, comprising optical elements (18) for imaging the radiation in an intermediate image plane (ZB), an adjustable diaphragm (8) according to one of Claims 1 until 12 in the intermediate image plane (ZB) and at least one optical element (20) for imaging the image of the adjustable diaphragm (8) in a sample space. Optical arrangement (15) after Claim 13 , having at least one correction unit (22) for compensating for imaging errors caused by the action of the adjustable diaphragm (8). Method for operating an adjustable diaphragm (8) according to one of Claims 1 until 12 , in which - for each screen element (1), whose current setting position is detected, with its actual formation being stored as a cam disk so that it can be called up repeatedly; - a desired and adjustable shape and size and/or position of the around the passage Axis (7) of the screen elements (1) partially limited opening (9) is determined; and - the screen elements (1) are moved into desired setting positions in accordance with the shape and size and/or position of the opening (9) to be set.

Images